Method for determining a matrix of transmission cross coefficients in an optical proximity correction of mask layouts

Abstract

The present invention relates to a method for determining a matrix of transmission cross coefficients w for an optical modeling in an optical proximity correction of mask layouts. In a first step, there is calculation of Fourier transforms of an illumination aperture, a lens aperture and a complex conjugate lens aperture, which are present in the form of image matrices with a predetermined raster. A second step involves calculating Fourier transforms for the transmission cross coefficients w from the Fourier transforms by means of a convolution theorem in order to obtain the matrix of the Fourier transforms of the transmission cross coefficients w. A further step involves inverse-transforming the Fourier transforms of the transmission cross coefficients w by means of a fast Fourier transformation in order to obtain the matrix of the transmission cross coefficients w for the optical modeling in the optical proximity correction of mass layouts.

Description

CLAIM FOR PRIORITY[0001]This application claims the benefit of priority to German Application No. 10 2004 030 961.2, filed Jun. 26, 2004, the contents of which are hereby incorporated by reference.TECHNICAL FIELD OF THE INVENTION[0002]The present invention relates to a method for determining a matrix of transmission cross coefficients for an optical modeling in an optical proximity correction of mask layouts, and to an optical proximity correction for a mask structure of a mask layout and also to a mask layout for a lithography mask with a mask structure.BACKGROUND OF THE INVENTION[0003]Particular patterning methods are used for fabricating large scale integrated electrical circuits with small structure dimensions. One of the most familiar methods known since the beginnings of semiconductor technology is the lithographic patterning method. In this case a radiation-sensitive resist or photoresist layer is applied to the surface of a semiconductor substrate wafer to be patterned and i...

AI Technical Summary

Benefits of technology

This approach significantly reduces computation time, enabling the use of fine raster image matrices for precise optical modeling and correction, resulting in faster and more accurate optical proximity correction for mask layouts, effectively compensating for imaging distortions.

Problems solved by technology

However, optical errors and process errors give rise to distortions of the imaged mask layout on the semiconductor substrate wafer.

Distortions of this type, which occur especially in the case of very small mask structures having structure sizes smaller than the wavelengths of the electromagnetic radiation used, consequently reduce the achievable resolution limit of the mask structures.

However, one disadvantage is that corrections of this type are inaccurate particularly in the case of very small structures and, as a result, imaging distortions may possibly be compensated for only inadequately.

However, if the apertures are given as “bitmaps” or image matrices which enable a more complex and precise description of the underlying lens system and the illumination settings, then the evaluation takes substantially longer depending on the desired accuracy or the size of the raster of the image matrices.

Consequently, an optical modeling carried out with a high accuracy requires a very high expenditure of time.

This expenditure of time can only be reduced by reducing the accuracy of the modeling and thus of the later correction run.

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